1. Field of the Invention
This invention relates to digital control systems and particularly to digital control systems having a thorough built in test equipment capability.
2. Description of the Prior Art
Digital control systems include processing units and analog and discrete input and output signal channels associated therewith. It is desirable that built in test equipment (BITE) be provided for testing the systems. When the systems are used for aircraft control purposes, the BITE should particularly provide simple and economical means for testing system line replacement units (LRU's) as is necessary for maintaining Federal Aviation Administration (FAA) Certification and such other certification as may be required.
Prior to the present invention, BITE for accomplishing the aforenoted purposes required that the flow of the system input signals be interrupted to accomplish the required testing. This affects the integrity of the testing and hence is a detriment to maintaining the aforenoted certification. The system of the present invention accomplishes the required testing without interrupting the signal flow and is thus a distinct improvement over like systems now known in the art.